Esters



Patented Aug. 30,1949

UNITED-STATES PATENT OFFICE ESTERS Harold Wittcofl, Minneapolis, Minn,assignor to General Mills, Inc., a corporation of Delaware No Drawing.Application June 16, 1945,

- Serial No. 599,948

12 Claims. 1.

The present invention relates to higher fatty acid esters of hydroxycompounds resulting from the condensation of formaldehyde with ketones.These condensation products may contain a single hydr'oxymethyl group ora plurality of hydroxymethyl groups depending upon the conditions of thecondensation. In addition, the ketone group may or may not be reduced toa hydroxyl group. In accordance with the present invention part or allof these hydroxyl groups may be esterified with higher fatty acidscontaining in excess of seven carbon atoms. The resulting products maybe drying. oils, plasticizers, waxes, emulsifying agents, surface activeagents, intermediates and the like depending upon the number of hydroxylgroups present in the condensation product, the extent to which thesehydroxyls have been esterified, and the nature of the acids used foresterification. I

It is, therefore, a primary object of the present invention to preparehigher fatty acid esters of hydroxy condensation products offormaldehyde with a ketone.

It is another object of the present invention to prepare higher fattyacid esters of mono or polyhydric condensation products of formaldehydewith a ketone, partially or completely esterified with higher fattyacids, the products possessing characteristics making them useful asdrying oils, plasticizers, waxes, emulsifying agents, surface activeagents, intermediates and the like.

These and other objects of the invention will be apparent from thefollowing description with particular reference to specific exampleswhich are to be considered as illustrative only and not as limiting theinvention.

In general, the invention involves the'p'repara tion of esters of fattyacids of more than seven carbon atoms, of hydroxy condensation productsof formaldehyde with a ketone. These esters include a wide variety ofcompounds in view of the variation which is possible in the ketone usedin the condensation, the extent of the condensation and accordingly thenumber of hydroxyl groups present in the condensation product, theextent to which the hydroxyl groups I are esterified, and the nature ofthe fatty acids employed for esterification. Thus the ketones may bealiphatic or alicyclic such as cyclohexanone, cyclopentanone, acetone,methyl ethyl ketone, diethyl ketone, mesityl oxide, diacetyl,acetonylacetone, diacetone alcohol, levulinic acid and the like.

Likewise, the fatty acids employed may be selected from a largegroup. Inthe preparation of drying oils the acids may be isolated or mixed acidsderived from drying or semi-drying oils such as cottonseed oil, soybeanoil, linseed oil,

perilla oil, tung oil, oiticica oil, sardine oil, menhaden oil, andother drying and semi-drying 2 oils in general. These acids may be inthe unchanged condition in which they exist in the natural oil or may heartificially conjugated, in

accordance with known methods. In the preparation of plasticizers,waxes, emulsifying agents,

' surface active agents, intermediates, and the like the acids may besaturated or unsaturated and may be composed of any suitable isolatedacid or mixture of acids. For preparing waxes it is usually desirable toemploy a high molecular weight saturated acid as this contributes to thehardness of the resultant wax.

46 (1896), and Apel and Tollens, Ber., 27, 1087 (1894). Improved methodsof preparing these condensation products will be found in the examplesof the present application and,in the co-pending application of thepresent inventor Serial No. 599,947 filed of even date herewith andentitled "Condensation of ketones with formaldehyde, now Patent No.2,462,031, issued February 15, 1949. The condensation reaction resultsin a mixture of products which may be of varying degrees ofhydroxylation and in some cases may be in the form of a sirupy liquid.It will be apparent thatthis mixture of condensation productsmay be usedin that condition for esterification if it is not desired to produce theester as a pure compound.

If the sirup is not readily crystallizable, and if a pure crystallinecondensation product is desired, it may be obtained in some instances byforming an aectal or ester or other derivative which may subsequently-behydrolyzed to the free hydroxy compound. The formation of an acetaloften takes place readily when the crude sirup is stirred, with acetone.Usually there is sufiicient acid present as a result of the methodofpreparation to catalyze acetal. formation. If necessary, a small amountof acid catalyst, such as sulfuric acid, may be added. As analternative, an acetal derivative maybe obtained by heating the sirup inaqueous methanol with an alydehyde such as benzaldehyde and a smallamount of mineral acid for a suitable period of time. The acetal may beisolated from the solution by filtration after which it may be purifiedby crystallization from a suitable solvent such as alcohol. The isolatedaectal derivative may be converted to the hydroxy compound by treatmentwith a strong acid, such as hydrochloric acid. The volatile ketone oraldehyde may then be distilled 01!, leaving the pure hydroxy compound asa light-colored oil which crystallizes readily on cooling. Where thealdehyde liberated is as high boiling as benzaldehyde, the applicationoi. vacuum or the use of steam distillation is desirable.

The esteriflcatlon with the fatty acid may be accomplished with eitherthe crude sirup or with the isolated pure hydroxy compound. Likewise, itis possible to esterify the acetal directly. This may be accomplishedunder the influence of an acid catalyst, preferably oxalic acid as iteffects the least amount of discoloration. Other strong acidiccatalysts. such as p-toluenesulfonic acid and sulfuric acid, maylikewise be used to catalyze this reaction.

. Where the free hydroxy compound is employed in the esteriflcation, anyof the well known processes of the prior art may be employed. Severaladvantageous procedures, however, have been evolved. In one case it hasbeen found possible to obtain excellent products by heating and stirringat around 200 C., equivalent quantities of the acid and thepolyfunctional alcohol for a period of three to four hours. Thepoiyfunctional alcohol. if it is used in a sirupy condition, mayadvantageously. be brought into contact with the other reagents bydissolving it in water. During the reaction the water is rapidly drivenoil. The color of the product is improved by the use of an inertatmosphere such as that providede by carbon dioxide or nitrogen whereasthe rate of esteriflcation is accelerated by the employment of a smallamount of catalyst such as the stearates, naphthenates, abietates. orother fat soluble salts of metals such as calicum, cadmium, cerium,strontium, zinc, and the like. Catalysts such as litharge, and those ofan acidic nature such as sulfuric acid and hydrogen chloride, may bevaluable in some cases. Near the end of the reaction the application ofa vacuum is valuable in order to remove the last trace of volatile orunreacted material. Following this general procedure then, it is easilypossible to obtain a product with an acid number and hydroxyl numberlower than 30. If still lower values are desired. heating may becontinued for a longer period of time. In cases where an oil is desiredwhich is completely free of any fatty acid, the material may bedissolved in petroleum ether or naphtha and titrated to neutrality withalcohol caustic. The precipitated soaps may then either be filtered offor extracted with aqueous ethanol. The product is then recovered fromthe hydrocarbon solution by desolvation. Another process of purificationwhich may be employed when an extremely pure oil is desired is that inwhich unreacted acid and highly hydroxylated or partially esterifledalcohol is extracted by the use of ethanol.

Still another method of esteriflcation which has been found particularlyadvantageous is that in which a small amount of a hydrocarbon solvent,such as xylene, is used for the purpose of removing the water ofesterification azeotropically. By controlling the amount of solventemployed, the temperature of the reaction mixture may be raised to anydesired degree. The advantage of this derives from the fact that anywater produced is readily removed thus driving the reaction in thedesired direction.

4 The esteriflcation may likewise be accomplished azeotropically by theuse of high boiling hydrocarbon solvent such as the isomerictriisopropylbenzenes in sufliclent'quantity to keep.

the soluble reactants and products in solution Here again an azeotropeis formed with thewater of esteriiication. This, however, is not assatisfactory as the use of a small amount of solvent such as xylenesince it requires the use of a large amount of solvent which because ofits low volatility is more difllcult to remove at the end of a reaction.In either case the apparatus may be arranged so that the azeotropesdistill in such a manner that the water is separated in the dis tillateand the hydrocarbon is returned to the reaction vessel.

The esters may be obtained also by a transestcriflcation reactionbetween the polyhydric alcohol and a glyceride such as soybean orlinseed oil or other esters of saturated or unsaturated higher fattyacids. Here again, an elevated temperature and stirring are advisabletogether with the use of catalysts such as oil soluble salts oi calcium,strontium, barium, vzinc, lithium. and the like.

The esters which are intended for waxes, emulsifying agents,plasticizers, etc. may be prepared by any of the previously mentionedesteriflcation procedures or by any or the other methods ofesteriiication commonly used in the art.

' Example 1.The soybean acid ester of the condensation product ofacetone and formaldehyde In a vessel equipped with an agitator and areflux condenser was placed 116 parts of acetone, 480 parts offormaldehyde in the form 01 paraformaldehyde and 1700 parts oi water.Thereafter- 56 parts of calcium oxide was added withstirring.'I'hereactionmixturethereuponwas heated to C. whereupon external heatingwas discontinued. The exothermic nature of the reaction caused thetemperature to rise to 90 C. whereupon the reaction mixture was cooledto room temperature. If desired, the same eifect may be attained bymaintaining the reaction mixture at a temperature of 50-55 C. for one tothree hours. The solution thereupon was treated with dilute sulfuricacid until it was barely acid to Congo red indicator. Oxalic acidsolution was added to make the reaction mixture strongly acid to Congored indicator and to precipitate the last traces of calcium ion. Theeasily illtrable precipitate of calcium sulfate and calcium oxalate wasremoved whereupon the aqueous solution was evaporated in vacuo. Thealmost water-white sirup which resulted was treated with an organicsolvent such as benzene and again evaporated in vacuo, the benzeneserving to remove occluded water azeotropically. The sirup whichresulted had a hydroxyl content or 28-30% and contained a substantialamount of an anhydroenneaheptitol which may be more accurately describedas tetrahydro-3,3,5,5-tetrakis (hydroxymethyl) -4-pyranol.

In a reaction vessel which was equipped with an agitator and a watertrap with condenser was placed 125 parts of the above described sirupycondensation product as an aqueous solution together with 520 parts ofsoybean fatty acids, 7 parts of calcium stearate, and parts of xylene orsimilar hydrocarbon solvent. The calcium stearate is useful as it servesto accelerate the reaction at first; it does not, however, appear todecrease the time required for heatber whose physical constants follow:

-conditions described in Example 1.

mg. The reaction mixture was stirred and heated under nitrogen for 4.5hours at a' temperature which started at 140 C. and which was grad.ually raised to 225 C. There resulted on removal of the xylene a productof low acid Specific gravity 25/25, 0.9493 Color (Gardner) 14-15Viscosity (Gardner), N

Iodine number, 122.8 Saponification equivalent, 331.4 Hydroxyl number,28.5

Acid number, less than 20 The drying times as compared with ordinarysoybean oil are indicated in the following table.

Tack Set, Drying compound hours hours hours Soybean oil 6 12 Soybeanester of the condensation roduct oi acetone and formaldeyde 3. 6 6.0 8.

Example 2.Linseed acid ester of the condensation product of acetone andformaldehyde In an appropriate vessel equipped with agitator was placed130 parts of the condensation product of acetone and formaldehyde ofExample 1, 400 parts of linseed fatty acids, and 5 parts of calciumstearate. The polyhydric alcohol was in the form of an aqueous solution.The reaction mixture was stirred vigorously and heated gradually undernitrogen, a temperature of 160 C. being maintained for two hours.Thereafter, the temperature was raised to 180 C. and gradually to 200 C.until there resulted a product with low acid number. The reconstitutedoil had the fol lowing physical properties,

The drying times as compared with ordinary linseed oil are indicated inthe following table.

Tack,

Set, hours y hours Compound hours Linseed oil 3 6 Linseed acid ester ofthe condensation product of acetone and formaldeiiyde 2 6 The dryingtests were conducted under the The fllm which resulted from thereconstituted oil was definitely superior to the film from ordinarylinnumv the time necessary for gelation to occur under a given set ofconditions. Whereas for the reconstituted oil sixty-four minutes wererequired, linseed oil required more than seven hours.

A crystalline diacetone derivative was obtained 'from the sirupycondensation product of acetone and formaldehyde of Example 1 byallowing a mixture of equal volumes of the sirup and acetone to remainovernight. There resulted a crystalline precipitate of a diacetonederivative of the anhydroenneaheptitol which was filtered andcrystallized several times from alcohol to yield a product melting at229 C. The formation of this material was catalyzed by the residual acidin the sirupy condensation product. This diacetone derivative wasdissolved. in a dilute solution 01 hydrochloric acid in order to effecthydrolysis after which the aqueous phase and the acetone which resultedfrom the cleavage was evaporated to yield a theoretical amount ofcrystalline anhydroenneaheptitol which on crystallization from alcoholyielded a product melting at 156 C. This product was shown by variousanalytical techniques to possess structure I.

The soybean acid ester of this material was prepared by reacting 70parts of it with 484 parts of soybean fatty acids in the presence of 10parts of calcium stearate. The reaction mixture was stirred and heatedunder nitrogen at 200-210 C. for four hours. In order to obtain aproduct which was entirely free of acid, the reaction mixture wasdissolved in a hydrocarbon solvent and neutralized with alcoholiccaustic. The resulting soaps were extracted with 70% ethanol Where uponthe solution was desolvated to yield a light colored reconstituteddrying oil whose desirable properties were similar to those of the oildescribed in Example 1.

Example 4.The linseed acid ester of the crystalline anhydroenneaheptitolresulting from the condensation product of acetone and formaldehy'de Thelinseed oilfatty acid ester of the crystalline anhydroenneaheptitol wasprepared exactly like the soybean ester described in the precedingexample to obtain a completely esterified material. Here again, the filmfrom the synthetic oil indicated the desirable characteristics ofgreater through dry," better spring, greater resistance toabrasion, andgreater hardness.

Example 5.The direct esterification with soy bean acids of diacetoneanhydroenneaheptitol The diacetone derivative of theanhydroenneaheptitol resulting from the condensation of acetone andformaldehyde was prepared as indicated in Example 3. In the presence ofan acidic catalyst this can be esterified directly since the acidiccatalyst serves to efiect the hydrolysis of the acetone groups. Thus amixture of 40 parts of the diacetone derivative with 190 parts ofsoybean fatty acids and 2.5 parts of oxalic acid was stirred and heatedat 200-210 C. under nitrogen. After one hour an additional 2.5 parts ofoxalic acid was added. The reaction mixture was heated for four hours toobtain a light colored, completely esterified reconstituted drying, oil.

Example 6.The partial ester of the condensation product of acetone andformaldehyde and stearic acid A mixture of 100 parts of the sirupycondensation product described in Example 1 as an 80% solution, togetherwith 290 parts of stearic acid and parts of calcium stearate was heatedat 210 C. under nitrogen for 2.5 hours. An ethanolic solution of theproduct was treated with charcoal, filtered and allowed to precipitateto yield a white solid melting at 57 C. The hydroxyl content of theproduct (3.2%) indicated two free hydroxyl groups. The acid content ofthe product was negligible. The product readily emulsified oleaginousmaterial such as vegetable oils and water when heated and shakenespecially in the presence of a small amount of dilute alkali. Theproducts of this nature are valuable as emulsifying agents in variousfood and pharmaceutical preparations.

Example 7.-The linseed acid ester of the reaction product of methylethyl ketone and formaldehyde In an appropriate vessel was placed 288parts of methyl ethyl ketone, 780 parts of formaldehyde asparaformaldehyde and 3000 parts of water. There was added slowly withstirring 112 parts of calcium oxide whereupon the temperature rosespontaneously to 50 C. Thereafter cooling was employed so that thetemperature would not rise higher and once the initial exothermicreaction had subsided, the reaction mixture was heated and stirred at50-55 C. for two hours. The product was worked up as described inExample 1 for the condensation product of acetone and formaldehyde toyield an almost colorless sirup whose hydroxyl content was of the orderof 30%. Because of the procedure used to remove the calcium ion theproduct was acidic in nature. This acidity could in large part beremoved by the use of a basic ion exchange resin such as AmberliteIR,-4. The sirupy product was used in the form of an aqueous solutionfor esterification purposes. The high hydroxyl content of the producttogether with certain other analytical investigations leads to theconclusion that the product is analogous to the one obtained fromacetone whereupon the structure of the chief constituent may bepostulated as desoxyanhydroenneaheptito] II.

CHzOH Specific gravity 25/25, 0.9153 Color (Gardner), 13-14 Viscosity(Gardner), A Hydroxyl number, 42.4

Acid number, 5.6

The reconstituted oil not only dried more rapidly than linseed oil butalso yielded a film exhibiting greater through dry," toughness, andresistance to abrasion and mild chemicals.

Example 8.The partial lauryl ester of the strupy condensation product ofmethyl ethyl ketone and formaldehyde A solution of 40 parts of thesirupy condensation product described in the preceding example in 300parts of pyridine and 200 parts of chloroform was treated with parts oflauroyl chloride with external cooling. After 20 hours the reactionmixture was poured over ice whereupon the product was extracted withether. The ether solution after having been Washed with dilute acid andwith water was dried and desolvated to yield a product which was an oilat room temperature but which solidified readily on cooling. Analyticaldata (2.1% OH) indicated that the product was approximately two-thirdsesterlfied. This material served as an emulsifying agent for vegetableoils in water, especially in the presence of a small amount of dilutealkali, and is valuable for use as an emulsifying agent in various foodand pharmaceutical preparations.

Ea'ample 9.The soy bean acid ester of the condensation product ofcyclopentanone and formaldehyde A reaction mixture consisting of 84parts of cyclopentanone, parts of paraformaldehyde, and 1200 parts ofwater was treated with 28 parts of calcium oxide after which thereaction mixture was heated and stirred at 60 C. for 30 minutes. Thefiltered solution was acidified to Congo red paper with dilute sulfuricacid solution whereupon the precipitated calcium sulfate was removed byfiltration and the filtrate was desolvated to yield an oil whosehydroxyl content was 27.4%. The hydroxyl content of 2,2,5,5-tetra,methylolcyclopentanone is 33.3%.

Fifty parts of this condensation product was reacted for 4 hours at200-210 C with stirring under nitrogen with 230 parts of soy bean acidsin the presence of 6 parts of calcium stearate. There resulted asynthetic drying oil with low acid number and a hydroxyl content whichindicated essentially complete esterification. The resulting film fromthis material was vastly superior to the film of soybean 011 indicatinggreater toughness and greater resistance to abrasion.

Example 10.The soybean acid ester of 2,2,6,6-

tetramethylolcyclohexanol In an appropriate vessel equipped withagitator and reflux condenser was placed 392 parts of .9 cyclohexanone,660 parts of formaldehyde in the form of paraformaldehyde, 3500 parts ofwater, and 112 parts of calcium oxide. With stirring the temperatureof'the solution rose spontaneously to 55 C. whereupon the exothermicnature of the reaction was checked by external cooling. Thereafter thereaction mixture was heated and stirred at 50-55 C. for two hours. Thereaction mixture after having been acidified to Congo red paper withdilute sulfuric acid was filtered and desolvated to yield a sirup whichcrystallized readily on trituration with alcohol. Crystallization fromabsolute ethanol yielded a product melting at 130-131 C. whose structureis indicated by III.

theoretical amount of water and the reaction mixture indicated a lowacid number. After removal of the xylene there resulted a product withthe following properties:

Specific gravity 25/25, 0.9474 Color (Gardner), 4

Viscosity (Gardner), E-F. Iodine number, 121.2 Saponificationequivalent, 339.2 Hydroxyl number, 33.5

Acid number, less than The drying times of this oil as compared withsoybean oil and linseed oil are indicated in the following table:

Tack, Set D y g. Compound hours hours hours Soybean on... e 12 Soybeanacid ester of 2,2,6,6-tetramethylolcyclohexanol 4 7 8. 5 Linseed Oil 3 68.5

The conditions used for this drying test were those indicated inExample 1. The film which resulted was tack-free and extremely resistantto abrasion, being superior not only to the film from soybean oil butalso to the film from linseed oil.

Example 11.The linseed acid ester of 2,2,6,6-

tetramethylolcyclohexanol The linseed acid ester of2,2,6,6-tetramethylolcyclohexanol was prepared similarly to the soybeanester described in the preceding example using 85 parts of the alcohol,454 parts of linseed fatty acid ester, 6 parts of calcium stearate, and90 parts of xylene. Heating and stirring under nitrogen was effected forfour hours at a temperature which was gradually raised from 165 C. to230 C. The light colored product had the following physical properties:

Specific gravity 25/25, 0.9545 Color (Gardner), 5 Viscosity (Gardner),D-E Iodine number, 154.2 Saponification equivalent, 334.4 Hydroxylnumber, 16.3

Acid number, 5

Brown heat time, 157 minutes The Brown heat time of ordinary linseed oilwas greater than seven hours. The drying times of this reconstituted oilcompared with linseed oil under the conditions outlined in Example 1 areindicated in the following table.

Tack Set Dr Compound hours hours hgs Linseed Oil 3 6 8. 5 Linseed acidester of 2,2,6,6-tetramethylolcyclohexanol 2 8. 6

Here again the film was more tack-free and indicated better through dryand better resistance to abrasion than did the corresponding film fromlinseed oil.

Example 12.The stearic acid ester of 2,2,63,6-

tetramethyloleyclohemanol A mixture of 50 parts of the polyhydricalcohol and 324 parts of stearic acid was heated at 210 C. withstirring. As soon as water was evolved the temperature was raised to 215C. whereupon a homogeneous reaction mixture resulted. Thereafter themixture was heated and stirred at this temperature for one hour, vacuumhaving been applied at the end of the reaction. The product was allowedto precipitate from 95% alcohol to yield a hard, white wax which meltedat 59 C. The'saponification equivalent of 311 (calculated 310.5) and thelow hydroxyl number of 6 indicated that the product was thepentastearate of 2,2,6,6-tetramethylolcyclohexanol. This materialpassessed very desirable wax-like properties particularly because of itsextreme hardness and pleasing light color.

Erample Iii-Varnish prepared from soybean acid ester of the condensationproduct of acetone and formaldehyde A mixture of 200 parts of thereconstituted oil described in Example 1 and 73 parts of a resin mixtureconsisting of approximately 12% ,phenolic type resin and 88% ester gumavailable commercially as Cooks HG-42 resin was heated at 280 c. for 795minutes at the end of which time it was possible to obtain a 24-inchstring. The reaction mixture was then diluted with 400 parts of mineralspirits.

The resulting varnish was treated with siccatives consisting of .02%cobalt and .02% manganese as the soluble naphthenates. The hardness ofthe resulting film was tested by the Rocker hardness procedure. thisfilm compared to the hardness of films of varnishes prepared fromsoybean oil, linseed oil,

and tung 'oil is indicated in the following table.

Varnish From- Hardness Tung oil 56. 4 Soybean acid ester of thecondensation product of acetone and formaldehyde 60. 1

Thus, it is seen that there resulted a varnish The hardness of mildchemicals such as 1% sodium hydroxide solution.

Example 14.Vamish jrom the linseed acid ester of the condensationproduct of acetone and formaldehyde The varnish was prepared accordingto the same formula indicated in the preceding example using thereconstituted oil described in Example 2. It was necessary to cook thevarnish only 3'75 minutes in order to obtain a 24-inch string. A similarvarnish using dehydrated castor oil required 525 minutes whereas avarnish of the same nature with linseed oil required 585 minutes. Theresulting varnish yielded a film which was harder than the film fromtung oil when tested by the Rocker procedure and which indicated greaterresistance to the action of hot and cold water and 1% sodium hydroxidesolution than did varnish from materials such as linseed oil.

Example 15.-Varnish prepared from the linseed acid ester of2,2,6,6-tetramethylolcyclohexano! In this case the oil prepared inExample 11 was subjected to the same varnish formulation indicated inExample 13. In this case 495 minutes were required in order to obtain a24-inch string. This, as reference to the preceding example willindicate, was faster than the time required for dehydrated castor oil orlinseed oil. The resulting film from this varnish indicated a hardnesson the Rocker scale of 80.5 as compared to 56.4 for tung oil. The filmlikewise was quite resistant to hot and cold water and sodium hydroxidesolution.

In addition to the resins indicated in these examples, other resins maybe used in preparing varnishes with the new synthetic drying oilsdescribed herein, as for example, ester gums, al-

kyds, polyindene, coumarone, phenolic type resins, or any of the resinscustomarily employed in making varnishes. It is particularly desirableto employ in varnishes, ester gums prepared according to my co-pendingapplication Serial No. 599,949, filed of even date herewith, entitledRosin acid esters, now Patent No. 2,470,964, issued May 24, 1949, and/oralkyds prepared according to my co-pending and now abandoned applicationSerial No. 599,950, filed of even date herewith entitled Alkyd resins.

In some casesin the preparation of varnish and similar coating materialsit is advisable to heat a reaction mixture consisting of a glyceridesuch as soybean oil, linseed oil, dehydrated castor oil, etc. with rosinacid and one of the polyhydric alcohols described in the co-pendingapplication entitled Condensation of ketones with formaldehyde. Insteadof ordinary gum or wood rosin or abietic acid such materials aspolymerized rosin, disproportionated rosin, hydrogenated rosin, or therosin portions of tall oil may be used. In such a reaction mixture,although the reaction is by nature complex, the glyceride is alcoholyzedyielding a partial fatty acid ester of glycerol and of theabove-mentioned polyhydric alcohol. The rosin acid serves to completethe esterification of these partial esters, yielding a very desirablecoating composition. If desired, a catalyst may be added to aid in thealcoholysis. This may consist of the abietate,

12 naphthenate, stearate, or other fat soluble salt of calcium, cadmium,cerium, strontium, zinc, and the like. The temperatures employed varyfrom 200-300- C. and the time of reaction may vary from 4 to 16 hoursdepending on the gbceridc employed and the temperature used.

While numerous examples of the invention have been given it will beapparent that other modifications are possible. It is to be understood,therefore, that the invention is limited only by the appended claims.

I claim as my invention:

1. An ester comprising a polyhydroxy condensation product having atleast four hydroxyl groups, said polyhydroxy condensation productresulting from the condensation of formaldehyde and a ketone having atleast four replaceable hydrogen atoms adjacent the carbonyl group, inwhich the molal ratio of formaldehyde to ketone is not substantiallyless than one mole of formaldehyde per mole of active hydrogen in theketone, said condensation product being substantially completelyesterified with a higher fatty acid.

2. An ester comprising a polyhydroiw condensation product having atleast four hydroxyl groups, said polyhydroxy condensation productresulting from the condensation of formaldehyde and an aliphatic ketonehaving at least four replaceable hydrogen atoms adjacent the carbonylgroup, in which the molal ratio of formaldehyde to ketone is notsubstantially less than one mole of formaldehyde per mole of activehydrogen in the ketone, said condensation product being substantiallycompletely esterified with a higher fatty acid.

3. An ester comprising a polyhydroxy condensation product having atleast four hydroxyl groups, said polyhydroxy condensation productresulting from the condensation of formaldehyde and an alicyclic ketonehaving at least four replaceable hydrogen atoms adjacent the carbonylgroup, in which the molal ratio of formaldehyde to ketone is notsubstantially less than one mole of formaldehyde per mole of activehydrogen in the ketone, said condensation product being substantiallycompletely esterified with a higher fatty acid.

4. An ester comprising a polyhydroxy condensation product having atleast four hydroxyl groups, said polyhydroxy condensation productresulting from the condensation of formaldehyde and a ketone having atleast four replaceable hydrogen atoms adjacent the carbonyl group, inwhich the molal ratio of formaldehyde to ketone is not substantiallyless than one mole of formaldehyde per mole of active hydrogen in theketone, said condensation product being substantially completelyesterified with the mixed fatty acids of a fatty oil.

5. An ester comprising a polyhydroxy condensation product having atleast four hydroxyl groups, said polyhydroxy condensation productresulting from the condensation of formaldehyde and a ketone having atleast four replaceable hydrogen atoms adjacent the carbonyl group, in

which the molal ratio of formaldehyde to ketone is not substantiallyless than one mole of formaldehyde per mole of active hydrogen in theketone, said condensation product being substantially completelyesterified with the mixed fatty acids of a drying oil.

6. An ester comprising a polyhydroxy condensation product having atleast four hydroxyl groups, said polyhydroxy condensation productresulting from the condensation of formalde-l hyde and a ketone havingat least four replaceable hydrogen atoms adjacent the carbonyl group, inwhich the molal ratio of formaldehyde to ketone is not substantiallyless than one mole of mormaldehyde per mole of active hydrogen in theketone, said condensation product being substantially completelyesterified with predominantly unsaturated higher fatty acids.

7. An ester comprising a polyhydroxy condensation product resulting fromthe condensation of formaldehyde and cyclohexanone, in which the molalratio of formaldehyde to cyclohexanone is not substantially less thanone mole of formaldehyde per mole of active hydrogenin thecyclohexanone, said condensation product being substantially completelyesterified with a higher fatty acid.

8. An ester comprising a polyhydroxy condensation product resulting fromthe condensation of formaldehyde and acetone, in which the molal ratioof formaldehyde to acetone is not substantially less than vone mole offormaldehyde per mole of active hydrogen in the acetone, saidcondensation product being substantially completely esterifled with ahigher fatty acid.

9. An ester comprising a polyhydroxy condensation product resulting fromthe condensation of formaldehyde and methyl ethyl ketone, in which themolal ratio of formaldehyde to methyl ethyl ketone. is not substantiallyless than one 1 mole of formaldehyde per mole of active hydrogen in themethyl ethyl ketone, said condensation product being substantiallycompletely es- 7 11. An ester comprising a polyhydroxy condensationproduct resulting from the condensation of formaldehyde and acetone, inwhich the molal ratio of formaldehyde to acetone is not substantiallyless than one mole of formaldehyde per mole of active hydrogen in theacetone, said condensation product being substantially completelyesterifled with an unsaturated higher fatty acid.

12. An ester comprising a polyhydroxy condensation product resultingfrom the condensation of formaldehyde and methyl ethyl ketone, in whichthe molal ratio of formaldehyde to methyl ethyl ketone is notsubstantially less than one mole of formaldehyde per mole of activehydrogen in the methyl ethyl ketone, said condensation product beingsubstantially completely esterifled with an unsaturated hi her fattyacid.

HAROLD WI'I'I'COFF.

REFERENCES CITED The following references are of record in the flle ofthis patent:

OTHER REFERENCES I Apel et 8.1., Annalen, vol. 289 (1896), pages 46-51.

